A deli sells small, medium and large sack lunches. Each bottle of water costs $1, and each apple costs $1. Each sandwich costs s dollars. Some customers buy sack lunches, and some customers buy items separately. Amy buys 8 sandwiches and 12 waters. Her total cost is 8s + 12. Bob buys 8 small sack lunches. These sack lunches include 1 sandwich, 1 water, and 1 apple. His total cost is 8(s + 2). Cathy buys 4 medium sack lunches. These sack lunches do not include water. Her total cost is 4(2s + 3).